Over the next three months he became increasingly depressed. He was found dead by his brothers Glen and Aaron at the family home in Callington Drive, Hattersley.

It was later discovered that since the initial spill incident, Mr Power's employers, P&R Laboratories, had sent him to other chemical works to clean up spills.

He often came home with chemical burns on his hands and once told Glen he'd lost his sense of smell after burning his nasal passages at work.

Barry, who lived with his parents, was said to have found the drive to work in St Helens such "a chore" he had planned to resign and return to university to complete a master's degree.

A month before his death, he changed his entry on the Friends Reunited website.

Glen told the court: "It went from cheery and breezy to very dark. It was if his mind had been altered in some way."

A post-mortem investigation found slight congestion in the windpipe and small changes to the heart muscle, but nothing conclusive to explain his death. Two toxicology tests came back negative.

His dad, also called Barry, believes he came into contact with polyurethane used in paints and foams. He claims studies show prolonged exposure can "alter the mind" and eventually "switch off" the brain.

However, only specialised toxicology tests would prove if this happened. These have never been carried out.

Coroner John Pollard said: "Considerable reference has been made to his working conditions, but it was not possible to find any link between that and his death."

After the inquest, Barry snr said: "We've had to force this issue since his death three years ago. If I have to pay for those tests myself I will. There are still no answers.

"All we are left with at the moment is a 29-year-old boy dead in a graveyard in Hyde."